US20110135341A1 - Fixing device and image forming apparatus - Google Patents
Fixing device and image forming apparatus Download PDFInfo
- Publication number
- US20110135341A1 US20110135341A1 US12/840,711 US84071110A US2011135341A1 US 20110135341 A1 US20110135341 A1 US 20110135341A1 US 84071110 A US84071110 A US 84071110A US 2011135341 A1 US2011135341 A1 US 2011135341A1
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- United States
- Prior art keywords
- housing
- roller
- belt
- concave portion
- positioning
- Prior art date
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- 238000001816 cooling Methods 0.000 description 5
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- 229910052751 metal Inorganic materials 0.000 description 4
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- 229920005989 resin Polymers 0.000 description 2
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- 229920002379 silicone rubber Polymers 0.000 description 2
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- 229920006026 co-polymeric resin Polymers 0.000 description 1
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- 238000012423 maintenance Methods 0.000 description 1
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- 238000010297 mechanical methods and process Methods 0.000 description 1
- 230000005226 mechanical processes and functions Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
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- 229920001721 polyimide Polymers 0.000 description 1
- 239000009719 polyimide resin Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
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Images
Classifications
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
- G03G21/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements
- G03G21/1661—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements means for handling parts of the apparatus in the apparatus
- G03G21/1685—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements means for handling parts of the apparatus in the apparatus for the fixing unit
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2215/00—Apparatus for electrophotographic processes
- G03G2215/20—Details of the fixing device or porcess
- G03G2215/2003—Structural features of the fixing device
- G03G2215/2016—Heating belt
- G03G2215/2025—Heating belt the fixing nip having a rotating belt support member opposing a pressure member
- G03G2215/2032—Heating belt the fixing nip having a rotating belt support member opposing a pressure member the belt further entrained around additional rotating belt support members
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G2221/00—Processes not provided for by group G03G2215/00, e.g. cleaning or residual charge elimination
- G03G2221/16—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts
- G03G2221/1639—Mechanical means for facilitating the maintenance of the apparatus, e.g. modular arrangements and complete machine concepts for the fixing unit
Definitions
- the present invention relates to a fixing device and an image forming apparatus that fixes an unfixed toner image on a recording medium.
- a fixing device used for an image forming apparatus of a copying machine or a printer one such device having a heating member constituted by a belt member (a fixing belt) provided with tension by plural rollers is known.
- a fixing device including: a belt unit that includes a first roller member, a second roller member provided above the first roller member, a belt member rotating while being laid around the first roller member and the second roller member, and a positioning member rotatably holding the first roller member and being used for positioning of the first roller member; a pressure member that is provided below the first roller member and comes into pressure-contact with an outer peripheral surface of the belt member at a position where the pressure member faces the first roller member, thereby to form a fixing pressure portion between the pressure member and the belt member, the fixing pressure portion allowing a recording medium carrying an unfixed toner image to pass therethrough; a first housing that includes a concave portion and a sloping portion formed therein and supports the positioning member, the concave portion opening toward a lateral direction, the sloping portion sloping downward from an edge portion of a lower side of the concave portion; and a second housing that presses the positioning member so that the positioning member is fitted into
- FIG. 1 is a diagram showing a configuration example of an image forming apparatus to which a fixing device according to the exemplary embodiment is applied;
- FIG. 2 is a sectional configuration diagram for illustrating a configuration of the fixing unit
- FIG. 3 is a diagram for illustrating a configuration of the belt unit in the fixing unit
- FIG. 4 is a diagram for illustrating a state in which the belt unit is mounted and positioned on the image forming apparatus
- FIG. 5 is a diagram for illustrating a state in which the belt unit is exposed in the image forming apparatus in order to replace the belt unit;
- FIG. 6 is a top view of FIG. 4 seen from a VI direction.
- FIG. 1 is a diagram showing a configuration example of an image forming apparatus 1 to which a fixing device (fixing unit) 60 according to the present exemplary embodiment is applied.
- the image forming apparatus 1 shown in FIG. 1 is a so-called “tandem-type” color printer, and includes: an image forming portion 10 which forms an image on the basis of image data; a main controller 50 which controls operations of the entire image forming apparatus 1 , performs communications with a personal computer (PC) and performs image processing on image data and the like, for example; and a user interface (UI) unit 90 which accepts an input operation made by the user and displays various information for the user.
- PC personal computer
- UI user interface
- the image forming portion 10 which is an example of a toner image forming unit, is a functional portion which forms an image through an electrophotographic system for example, and includes six image forming units 11 C, 11 M, 11 HC, 11 HM, 11 Y, and 11 K (hereinafter, also referred to as “image forming units 11 ” collectively), which are arranged in parallel.
- each of the image forming units 11 includes, as functional members: a photoconductive drum 12 on which an electrostatic latent image is formed and thereafter a toner image of each color is formed; a charging device 13 which charges the surface of the photoconductive drum 12 at a predetermined electric potential; an exposure device 14 which exposes the photoconductive drum 12 on the basis of image data, the photoconductive drum 12 charged by the charging device 13 ; a developing device 15 which develops the electrostatic latent image formed on the photoconductive drum 12 by using a toner of each color; and a cleaner 16 which cleans the surface of the photoconductive drum 12 after transfer.
- the developing devices 15 of the respective image forming units 11 are connected through toner transport paths (not shown) to toner containers 17 C, 17 M, 17 HC, 17 HM, 17 Y, and 17 K (hereinafter, also referred to as “toner containers 17 ” collectively), and are configured to be refilled with color toners from the toner containers 17 through refill screws (not shown) provided in the toner transport paths.
- the toner containers 17 store the respective color toners.
- the image forming units 11 have similar configurations except toners housed in the respective developing devices 15 , and form toner images of the respective colors of cyan (C), magenta (M), high-saturation cyan (HC), high-saturation magenta (HM), yellow (Y) and black (K).
- C cyan
- M magenta
- HC high-saturation cyan
- HM high-saturation magenta
- K black
- HC has a hue of cyan, and has a light color tone and high saturation relative to those of C.
- HM has a hue of magenta, and has a light color tone and high saturation relative to those of M.
- the image forming portion 10 also includes: an intermediate transfer belt 20 on which the color toner images formed on the photoconductive drums 12 of the respective image forming units 11 are transferred; primary-transfer rollers 21 which transfer (primary-transfer) the color toner images on the intermediate transfer belt 20 , the color toner images being formed by the image forming units 11 ; a secondary-transfer roller 22 which collectively transfers (secondary-transfers), to a sheet that is a recording medium (recording sheet), the color toner images transferred on the intermediate transfer belt 20 in a superimposing manner; and the fixing unit 60 as an example of a fixing unit (fixing device) which fixes the secondary-transferred color toner images on the sheet.
- an intermediate transfer belt 20 on which the color toner images formed on the photoconductive drums 12 of the respective image forming units 11 are transferred
- primary-transfer rollers 21 which transfer (primary-transfer) the color toner images on the intermediate transfer belt 20 , the color toner images being formed by the image forming units 11
- the image forming portion 10 includes: a cooling unit 80 which cools the color toner images fixed on the sheet by the fixing unit 60 so as to facilitate the fixing of the color toner images on the sheet; and a curl correcting unit 85 which corrects curl of the sheet.
- the intermediate transfer belt 20 , the primary-transfer rollers 21 and the secondary-transfer roller 22 constitute a transfer unit. Further, hereinafter, a region in which the secondary-transfer roller 22 is placed to secondary-transfer the color toner images, which have been transferred on the intermediate transfer belt 20 , onto the sheet will be referred to as “secondary-transfer region Tr.”
- the image forming portion 10 also includes, as a sheet transporting system: multiple (two in the present exemplary embodiment) sheet containers 40 A and 40 B which house sheets therein; feed rollers 41 A and 41 B which feed and transport sheets housed in the sheet containers 40 A and 40 B; a first transport path R 1 which is used for transporting a sheet fed from the sheet container 40 A; a second transport path R 2 which is used for transporting a sheet fed from the sheet container 40 B; a third transport path R 3 which is used for transporting the sheet fed from the sheet container 40 A or 40 B toward the secondary-transfer region Tr; a fourth transport path R 4 which is used for transporting the sheet, on which the color toner images are transferred in the secondary-transfer region Tr, so as to cause the sheet to pass through the fixing unit 60 , the cooling unit 80 and the curl correcting unit 85 ; and a fifth transport path R 5 which is used for transporting the sheet from the curl correcting unit 85 toward a sheet stacking unit 44 provided to an output portion of the image forming apparatus 1 .
- Transport rollers or transport belts are arranged on each of the first to fifth transport paths R 1 to R 5 to sequentially transport sheets fed on their corresponding path.
- the image forming portion 10 also includes, as a duplex transporting system: an intermediate sheet container 42 which once holds a sheet on a first surface of which the color toner images are fixed by the fixing unit 60 ; a sixth transport path R 6 which is used for transporting a sheet from the curl correcting unit 85 toward the intermediate sheet container 42 ; a seventh transport path R 7 which is used for transporting a sheet housed in the intermediate sheet container 42 toward the third transport path R 3 ; a routing mechanism 43 which is arranged downstream of the curl correcting unit 85 in a sheet transport direction, and selects the route of a sheet between the fifth transport path R 5 and the sixth transport path R 6 , the fifth transport path R 5 used for transporting the sheet toward the sheet stacking unit 44 , the sixth transport path R 6 used for transporting the sheet toward the intermediate sheet container 42 ; feed rollers 45 which feed a sheet housed in the intermediate sheet container 42 and transport the sheet toward the seventh transport path R 7 .
- a duplex transporting system an intermediate sheet container 42 which once holds a sheet
- the image forming units 11 of the image forming portion 10 form toner images of the respective colors of C, M, HC, HM, Y and K with an electrophotographic process using the functional members described above.
- the color toner images formed by the respective image forming units 11 are primary-transferred on the intermediate transfer belt 20 sequentially by the primary-transfer rollers 21 , so that a combined toner image in which the color toners are superimposed is formed.
- the combined toner image on the intermediate transfer belt 20 is transported to the secondary-transfer region Tr in which the secondary-transfer roller 22 is arranged.
- the feed rollers 41 A and 41 B rotate in concert with the start timing of the image forming operation performed by the image forming units 11 .
- one of sheets in the sheet container 40 A or 40 B is fed by the corresponding feed roller 41 .
- the selection between the sheet containers 40 A and 40 B is made through the UI unit 90 , for example.
- the sheet fed by the feed roller 41 A or 41 B is transported to the secondary-transfer region Tr along the first transport path R 1 or the second transport path R 2 , and the third transport path R 3 .
- the combined toner image held on the intermediate transfer belt 20 is secondary-transferred on the sheet collectively with a transfer electric field formed by the secondary-transfer roller 22 .
- the sheet on which the combined toner image is transferred is thereafter separated from the intermediate transfer belt 20 , and transported to the fixing unit 60 along the fourth transport path R 4 .
- the fixing unit 60 performs a fixing process on the combined toner image formed on the sheet transported thereto, and thereby fixes the toner image on the sheet.
- the sheet having the fixed image formed thereon is then cooled by the cooling unit 80 , and its curl is corrected by the curl correcting unit 85 .
- the sheet having passed through the curl correcting unit 85 is thereafter routed by the routing mechanism 43 . In the case of simplex printing, the sheet is guided to the fifth transport path R 5 so as to be transported toward the sheet stacking unit 44 .
- the toner attached to each photoconductive drum 12 after the primary-transfer (primary-transfer residual toner) is removed by the corresponding cleaner 16
- the toner attached to the intermediate transfer belt 20 after the secondary-transfer (secondary-transfer residual toner) is removed by a belt cleaner 26 .
- the sheet In the case of duplex printing, the sheet, on the first surface of which the fixed image is formed through the aforementioned process, passes through the curl correcting unit 85 and is then guided by the routing mechanism 43 to the sixth transport path R 6 so as to be transported toward the intermediate sheet container 42 . Then, the feed rollers 45 rotate in concert with the start timing of an image forming operation for a second surface performed by the image forming units 11 , and the sheet is thereby fed from the intermediate sheet container 42 . The sheet fed by the feed rollers 45 is transported to the secondary-transfer region Tr along the seventh and third transport paths R 7 and R 3 .
- color toner images for the second surface which are held on the intermediate transfer belt 20 are secondary-transferred on the sheet collectively with a transfer electric field formed by the secondary-transfer roller 22 .
- the sheet, both surfaces of which the toner images are formed, is subjected to the fixing process by the fixing unit 60 , cooled by the cooling unit 80 , and its curl is corrected by the curl correcting unit 85 , as in the case of the operation for the first surface.
- the sheet having passed through the curl correcting unit 85 is then guided by the routing mechanism 43 to the fifth transport path R 5 so as to be transported toward the sheet stacking unit 44 .
- the image forming process of the image forming apparatus 1 is repeatedly performed in the aforementioned manner until cycles corresponding to the number of sheets to be printed have elapsed.
- FIG. 2 is a sectional configuration diagram for illustrating a configuration of the fixing unit 60 according to the present exemplary embodiment.
- the fixing unit 60 is mainly formed of: a fixing belt module 61 heating a sheet; an outer heating roller 613 as an example of an outer heating member which heats a fixing belt 610 provided to the fixing belt module 61 , while tensioning the fixing belt 610 from the outer side thereof; and a pressure roller 62 as an example of a pressure member which is configured in such a way that the pressure roller 62 may come into contact with and separate from the fixing belt module 61 .
- the fixing belt module 61 includes: the fixing belt 610 as an example of a belt member which moves circularly; a fixing roller 611 as an example of a first roller member which rotates while tensioning the fixing belt 610 , and heats the fixing belt 610 from the inner side thereof at a nip portion N as an example of a fixing pressure portion that is a region where the fixing belt module 61 and the pressure roller 62 are in pressure-contact with each other (i.e., in contact with each other while pressing each other); an inner heating roller 612 as an example of a second roller member which heats the fixing belt 610 while tensioning the fixing belt 610 from the inner side thereof.
- the fixing belt module 61 includes: a tension roller 614 which tensions the fixing belt 610 between the fixing roller 611 and the inner heating roller 612 (i.e., at the upstream side of the nip portion N in a belt movement direction); a peeling pad 64 as an example of a peeling member which is arranged downstream of the nip portion N in the belt movement direction and near the fixing roller 611 ; a tension roller 615 which tensions the fixing belt 610 between the nip portion N and the outer heating roller 613 (at the downstream side of the nip portion N in the belt movement direction); and a support roller 616 which supports the fixing belt 610 while receiving pressing force from the outer heating roller 613 .
- a tension roller 614 which tensions the fixing belt 610 between the fixing roller 611 and the inner heating roller 612 (i.e., at the upstream side of the nip portion N in a belt movement direction)
- a peeling pad 64 as an example of a peeling member which is arranged
- the fixing belt 610 is formed of: a base layer which is made of polyimide resin; an elastic body layer which is stacked on the surface (outer peripheral surface) of the base layer and made of silicone rubber; and a release layer which covers the elastic body layer and is made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin), for example.
- the elastic body layer is provided for improving quality of color images in particular.
- the elastic body layer is provided for the following reason.
- a toner image held on the sheet on which the toner image is to be fixed is formed by stacking powdery color toners. Accordingly, in order to uniformly heat the entire toner image at the nip portion N, the front surface of the fixing belt 610 may be deformed to follow the surface irregularities of the toner image on the sheet.
- the fixing roller 611 is a cylindrical roller made of aluminum or SUS, for example.
- the fixing roller 611 is rotated in its arrow direction in FIG. 2 by the rotational driving force of an unillustrated driving motor, and heated to a predetermined temperature (150° C., for example) by three halogen heaters 71 , for example, as an example of a heat source placed inside the fixing roller 611 .
- the inner heating roller 612 is a cylindrical roller made of aluminum or SUS, for example.
- the inner heating roller 612 is heated to a predetermined temperature (190° C., for example) by four halogen heaters 72 , for example, as an example of a heat source placed inside the inner heating roller 612 .
- a spring member (not shown) is arranged at both end portions of the inner heating roller 612 .
- the spring member presses the fixing belt 610 from the inner side thereof, and thereby sets the tension of the entire fixing belt 610 at, for example, 15 kgf.
- the inner heating roller 612 is further provided with a mechanism (not shown) for controlling the meandering (belt walk) of the fixing belt 610 .
- the peeling pad 64 is a block member formed of metal such as SUS or resin, for example, and having an arc-shaped cross section.
- the peeling pad 64 is fixedly arranged over the entire area of the fixing roller 611 in its axial direction at a position downstream of a region where the pressure roller 62 is to come into pressure-contact with the fixing roller 611 with the fixing belt 610 interposed therebetween (such a region is hereinafter called a “roller nip portion N 1 ”).
- the peeling pad 64 is arranged to uniformly press, at a predetermined load (at an average of 10 kgf, for example), the pressure roller 62 in a predetermined width region (over a nip width of 5 mm in the movement direction of the fixing belt 610 , for example) with the fixing belt 610 interposed therebetween.
- a predetermined load at an average of 10 kgf, for example
- Such a width region forms a “peeling pad nip portion N 2 ” adjacent to the roller nip portion N 1 .
- the outer heating roller 613 has its base made of aluminum or SUS, for example, and is a cylindrical roller formed by a surface thereof being subjected to nitriding, for example.
- the outer heating roller 613 is heated to a predetermined temperature (190° C., for example) by three halogen heaters 73 , for example, placed inside the outer heating roller 613 .
- the fixing unit 60 of the present exemplary embodiment employs a configuration in which the fixing belt 610 is heated by the fixing roller 611 , the inner heating roller 612 and the outer heating roller 613 .
- the fixing belt module 61 the fixing belt 610 , the fixing roller 611 , the inner heating roller 612 , the tension roller 614 , the tension roller 615 , the support roller 616 and the peeling pad 64 except the outer heating roller 613 configure a belt unit 600 provided to the image forming apparatus 1 so as to be attachable and detachable. Detail of the belt unit 600 will be described later.
- the pressure roller 62 has, as its base, a cylindrical roller made of aluminum or SUS, for example, and has an elastic layer made of silicone rubber, and a release layer made of a PFA tube which are stacked in this order from the base side.
- the pressure roller 62 is arranged in such a way that it may come into contact with and separate from the fixing belt module 61 .
- the pressure roller 62 is rotated with the rotation of the fixing roller 611 of the fixing belt module 61 in its arrow direction.
- a combined toner image (unfixed toner image) is electrostatically transferred on the sheet in the secondary-transfer region Tr (see FIG. 1 ), and the sheet is then transported toward the nip portion N (see FIG. 2 ) of the fixing unit 60 along the fourth transport path R 4 (see FIG. 1 ).
- the unfixed toner image on the sheet is fixed on the sheet mainly by pressure and heat acting on the roller nip portion N 1 .
- heat to act on the roller nip portion N 1 is supplied mainly through the fixing belt 610 .
- the fixing belt 610 is heated by: heat supplied by the halogen heaters 71 placed inside of the fixing roller 611 through the fixing roller 611 ; heat supplied by the halogen heaters 72 placed inside of the inner heating roller 612 through the inner heating roller 612 ; and heat supplied by the halogen heaters 73 placed inside of the outer heating roller 613 through the outer heating roller 613 .
- This configuration allows thermal energy to be supplied not only through the fixing roller 611 but also through the inner heating roller 612 and the outer heating roller 613 . Accordingly, a sufficient amount of heat supply is secured in the roller nip portion N 1 even at a high process speed.
- the fixing belt 610 serving as a direct fixing member may have a configuration with extremely low heat capacity.
- the fixing belt 610 is configured to be in contact with each of the fixing roller 611 , the inner heating roller 612 , and the outer heating roller 613 , which are heat supplying members, in a large wrap area (wrap angle).
- This configuration allows a sufficient amount of heat to be supplied through the fixing roller 611 , the inner heating roller 612 , and the outer heating roller 613 in a short period in which the fixing belt 610 makes one rotation, and thereby allows the fixing belt 610 to come back to a required fixing temperature within a short time period.
- the predetermined fixing temperature is maintained in the roller nip portion N 1 .
- a fixing temperature is maintained within a certain range even when sheets are continuously fed at a high speed.
- a phenomenon in which the fixing temperature drops at the start of high-speed fixing operation is suppressed.
- the fixing roller 611 is a hard roller made of aluminum, SUS, or the like, while the pressure roller 62 is a soft roller made by covering the elastic layer. Accordingly, in the roller nip portion N 1 , a nip region having a certain width in the movement direction of the fixing belt 610 is formed by the pressure roller 62 being bent at its surface with the fixing roller 611 being hardly bent. As described above, in the roller nip portion N 1 , the fixing roller 611 around which the fixing belt 610 is wound is hardly deformed.
- the sheet After passing through the roller nip portion N 1 , the sheet is subsequently transported to the peeling pad nip portion N 2 .
- the pressure roller 62 presses the peeling pad 64 , and thereby comes into pressure-contact with the fixing belt 610 .
- Such a configuration causes the peeling pad nip portion N 2 to have curving upward with the curvature of the pressure roller 62 , while the roller nip portion N 1 has a shape curving downward with the curvature of the fixing roller 611 .
- the sheet which has been heated and pressurized with the curvature of the fixing roller 611 in the roller nip portion N 1 , is caused to change its movement direction in the peeling pad nip portion N 2 along the curvature of the pressure roller 62 , which is opposite to the current direction.
- an extremely little slippage occurs between the toner image on the sheet and the surface of the fixing belt 610 .
- the peeling pad nip portion N 2 may be regarded as a region where a preparation step is carried out for ensuring reliable peeling in a final peeling step.
- the transport direction of the fixing belt 610 is changed there.
- the fixing belt 610 moves along the outer side surface of the peeling pad 64 , the fixing belt 610 is bent to a large extent at the exit of the peeling pad nip portion N 2 .
- the sheet, whose adhesion force to the fixing belt 610 has been weakened in advance in the peeling pad nip portion N 2 is peeled from the fixing belt 610 by the stiffness of the sheet itself.
- the sheet having been peeled from the fixing belt 610 is then moved in a direction guided by a peeling guide plate 69 which is arranged downstream of the peeling pad nip portion N 2 .
- the sheet having been guided by the peeling guide plate 69 is thereafter transported toward the cooling unit 80 by a sheet exit guide 78 and a sheet exit belt 79 .
- the fixing process in the fixing unit 60 is completed with the above-described operation.
- FIG. 3 is a diagram for illustrating a configuration of the belt unit 600 in the fixing unit 60 . Note that FIG. 3 shows a side elevational view of the belt unit 600 seen from the front side thereof in FIG. 1 .
- the belt unit 600 includes: a support housing 601 which is formed of metal, such as SUS, rotatably supports roller members, such as the fixing roller 611 , the tension roller 614 , the tension roller 615 and the support roller 616 , and supports members, such as the peeling pad 64 , in a fixed state; and a roller support member 602 which is formed of metal, such as SUS, rotatably supports the inner heating roller 612 .
- the roller support member 602 is supported by a slide support member 603 arranged between the support housing 601 and the roller support member 602 so as to slide (move in parallel) in the direction of a rotation axis 612 a of the inner heating roller 612 .
- roller support member 602 supports the rotation axis 612 a of the inner heating roller 612 by using a roller support portion 602 a. This configuration allows the inner heating roller 612 to rotate through a bearing (not shown) arranged between the inner heating roller 612 and the rotation axis 612 a supported by the roller support portion 602 a.
- the roller support portion 602 a supporting the rotation axis 612 a of the inner heating roller 612 is provided with a low friction portion 602 b made of a low friction member such as PFA, for example, which lowers sliding resistance between the rotation axis 612 a and the roller support portion 602 a.
- a low friction portion 602 b made of a low friction member such as PFA, for example, which lowers sliding resistance between the rotation axis 612 a and the roller support portion 602 a.
- the support housing 601 includes a roller biasing member 604 attached thereto.
- the roller biasing member 604 biases the roller support member 602 toward the rotation axis 612 a of the inner heating roller 612 .
- the roller biasing member 604 applies force toward an outer side (upward in FIG. 3 ) to the inner heating roller 612 with the roller support member 602 interposed therebetween, and thereby sets predetermined tension to the fixing belt 610 which tensions the inner heating roller 612 .
- a rotation axis 611 a of the fixing roller 611 is arranged in such a way that the rotation axis 611 a penetrates a bore provided to the support housing 601 to project into the front side of the support housing 601 in FIG. 3 .
- an unillustrated bearing is provided at a position where the bore is formed.
- the support housing 601 rotatably supports the rotation axis 611 a of the fixing roller 611 .
- a bearing member 605 which is rotatable with respect to the rotation axis 611 a is mounted on a portion of the rotation axis 611 a of the fixing roller 611 , the portion being arranged so as to project toward the outer side from the support housing 601 .
- the bearing member 605 as an example of a positioning member is used for an operation to attach or detach the belt unit 600 and positioning of the belt unit 600 with respect to the image forming apparatus 1 .
- a holding pin 606 which projects toward the front side in FIG. 3 is attached to the support housing 601 on the inner heating roller 612 side thereof.
- the holding pin 606 as an example of a second positioning member is used for an operation to attach or detach the belt unit 600 and positioning of the belt unit 600 with respect to the image forming apparatus 1 , as well as the bearing member 605 mentioned above.
- the support housing 601 and the roller support member 602 are provided to the fixing roller 611 and the like on each of the front and rear sides in FIG. 3 .
- the slide support member 603 , the roller biasing member 604 , the bearing member 605 and the holding pin 606 are also provided on each of the front and rear sides in FIG. 3 , respectively.
- a gear (not shown) for receiving driving force from the driving motor (not shown) provided on the main body of the image forming apparatus 1 is attached to the rotation axis 611 a of the fixing roller 611 projecting toward the rear side in FIG. 3 .
- FIG. 4 is a diagram for illustrating a state in which the belt unit 600 is mounted and positioned on the image forming apparatus 1 .
- FIG. 5 is a diagram for illustrating a state in which the belt unit 600 is exposed in the image forming apparatus 1 in order to replace the belt unit.
- FIG. 6 is a top view of FIG. 4 seen form a VI direction.
- the image forming apparatus 1 of the present exemplary embodiment includes: a main body housing 110 which is mounted on the image forming apparatus 1 in a fixed state, and rotatably supports the pressure roller 62 constituting the fixing unit 60 ; a movable housing 120 which is attached to the main body housing 110 so as to be openable and closeable.
- the main body housing 110 as an example of a first housing and the movable housing 120 as an example of a second housing are rotatably connected with each other by an axis 100 provided below.
- the main body housing 110 and the movable housing 120 are connected with each other by an unillustrated spring above the axis 100 . This unillustrated spring restrains the movable housing 120 from rotating in the clockwise direction in FIG.
- Rotation of the movable housing 120 in the clockwise direction in FIG. 4 around the axis 100 with respect to the main body housing 110 exposes the belt unit 600 to the outside. Meanwhile, rotation of the movable housing 120 in the counterclockwise direction in FIG. 4 around the axis 100 with respect to the main body housing 110 covers the belt unit 600 from the outside.
- the main body housing 110 is formed of two side plates connected with a member extending from the front side to the rear side in FIG. 4 .
- the two side plates are obtained by performing a mechanical process on a metal plate, for example, and are respectively provided on the front side and the rear side of a mounting portion of the belt unit 600 .
- the main body housing 110 is provided with a pin receiving portion 111 which opens upward and is used for inserting the holding pin 606 attached to the support housing 601 of the belt unit 600 .
- the pin receiving portion 111 as an example of a receiving portion is formed in such a way that the pin receiving portion 111 has a slightly larger diameter than that of the holding pin 606 in an upper region which is an entrance/exit of the holding pin 606 , and has a larger diameter in a lower region than in the upper region.
- the main body housing 110 is provided with a bearing fitted portion 112 which opens toward a lateral side facing the movable housing 120 , and into which the bearing member 605 of the belt unit 600 is fitted.
- the bearing fitted portion 112 as an example of a concave portion has a semicircular opening shape along the bearing member 605 .
- the bearing fitted portion 112 is provided with, at the lower end portion thereof: a sloping portion 113 formed in such a way that an edge thereof is lowered with a slope toward the movable housing 120 ; and a flat portion 114 which is connected to the sloping portion 113 and has a flat edge.
- the main body housing 110 includes: a first fixed opening 115 provided at the upside thereof in the up-and-down direction; and a second fixed opening 116 provided at a position that is horizontal with the axis 100 on a distal side seen from the pressure roller 62 with respect to a position where the axis 100 is formed.
- the movable housing 120 is formed of a material obtained by resin molding or the like, for example, and has an L-shaped cross section.
- the movable housing 120 is provided with a support portion 121 which rotatably supports the outer heating roller 613 constituting the fixing unit 60 . This configuration allows the outer heating roller 613 to rotate around the axis 100 in accordance with the movable housing 120 .
- the movable housing 120 includes a pressing member 122 attached thereto.
- the pressing member 122 presses the bearing member 605 against an edge of the inner heating roller 612 by pressing the bearing member 605 fitted into the bearing fitted portion 112 of the main body housing 110 toward the main body housing 110 from a lateral side of the bearing member 605 , when the movable housing 120 is closed with respect to the main body housing 110 in a state where the belt unit 600 is arranged.
- the pressing member 122 as an example of a second pressing member is attached to the movable housing 120 through a spring 123 as an example of an elastic member, so as to be capable of advancing and retracting with respect to the movable housing 120 .
- the movable housing 120 includes a regulation portion 124 formed therein. As shown in FIG. 5 , the regulation portion 124 regulates further movement of the bearing member 605 by coming into contact with the bearing member 605 , when the movable housing 120 is opened with respect to the main body housing 110 in the state where the belt unit 600 is arranged, and the bearing member 605 is removed from the bearing fitted portion 112 provided to the main body housing 110 .
- the regulation portion 124 has a structure in which two flat surfaces are connected with each other by one sloping surface. The height of a flat surface at a portion of the regulation portion 124 adjacent to the pressing member 122 is the same as that of a surface of the pressing member 122 .
- the regulation portion 124 functions as a first pressing member which presses the bearing member 605 toward the bearing fitted portion 112 , as will be described later.
- the movable housing 120 includes: a first movable opening 125 provided on an upper edge thereof; and a second movable opening 126 provided on a lower edge thereof.
- the second fixed opening 116 provided to the main body housing 110 and the second movable opening 126 provided to the movable housing 120 overlap each other when the movable housing 120 is opened with respect to the main body housing 110 , as shown in FIG. 5 .
- the image forming apparatus 1 further includes fastening members 130 .
- the fastening members 130 fasten the movable housing 120 to the main body housing 110 by penetrating the first fixed opening 115 and the first movable opening 125 , which are overlapped each other, when the movable housing 120 is closed with respect to the main body housing 110 , as shown in FIGS. 4 and 6 , for example.
- the fastening members 130 fasten the movable housing 120 to the main body housing 110 by penetrating the second fixed opening 116 and the second movable opening 126 , which are overlapped each other, when the movable housing 120 is opened with respect to the main body housing 110 , as shown in FIG. 5 , for example.
- Each of the fastening members 130 includes: a grip portion 131 for a user to hold by hand; and a fastening pin 132 which is attached to the grip portion 131 and is capable of being inserted into each of the aforementioned openings.
- FIGS. 4 to 6 a procedure removing the belt unit 600 from the image forming apparatus 1 is described with reference to FIGS. 4 to 6 .
- the image forming apparatus 1 is supposed to be as shown in FIG. 4 in an initial state.
- an opening operation to open the movable housing 120 closed with respect to the main body housing 110 is performed.
- the fastening members 130 which fasten the movable housing 120 to the main body housing 110 are removed from above. This causes the movable housing 120 to be rotatable around the axis 100 with respect to the main body housing 110 . However, removal of the fastening members 130 does not release the movable housing 120 with respect to the main body housing 110 because the movable housing 120 is pulled toward the main body housing 110 by the unillustrated spring connected between the main body housing 110 and the movable housing 120 .
- the pressing member 122 provided to the movable housing 120 moves in a direction apart from the bearing member 605 provided to the belt unit 600 held in the main body housing 110 .
- the outer heating roller 613 attached to the support portion 121 provided to the movable housing 120 also separates from the fixing belt 610 provided to the belt unit 600 .
- the bearing member 605 is pressed on an upper edge of the bearing fitted portion 112 by the pressure roller 62 , while the holding pin 606 is held on the main body housing 110 side in a state where the holding pin 606 is loosely fitted into the pin receiving portion 111 .
- the second movable opening 126 provided to the movable housing 120 reaches a position at which the second movable opening 126 overlaps with the second fixed opening 116 provided to the main body housing 110 .
- the fastening members 130 which are previously removed, are prepared and inserted from a lateral side so that the fastening pin 132 of each fastening member 130 penetrates the second fixed opening 116 and the second movable opening 126 .
- the movable housing 120 is fastened in an opened state with respect to the main body housing 110 while resisting the pulling force of the unillustrated spring. That is, the state of the main body housing 110 and the movable housing 120 changes to that shown in FIG. 5 . Additionally, the belt unit 600 is exposed between the main body housing 110 and the movable housing 120 in accordance with this change.
- the bearing member 605 provided to the belt unit 600 starts moving toward a side (right side in FIG. 5 ) being apart from the bearing fitted portion 112 of the main body housing 110 .
- the bearing member 605 slides down along the sloping portion 113 of the main body housing 110 due to the gravity applied to the belt unit 600 .
- the bearing member 605 having slid down along the sloping portion 113 then bumps into the flat portion 114 of the main body housing 110 at a part of the peripheral surface of the bearing member 605 , and stops by another part of the peripheral surface thereof bumping into the regulation portion 124 of the movable housing 120 .
- the holding pin 606 is loosely fitted into the pin receiving portion 111 provided to the main body housing 110 . Accordingly, in accordance with the aforementioned slide down of the bearing member 605 along the sloping portion 113 , the holding pin 606 moves downward in a state where the holding pin 606 is restrained from moving in the lateral direction thereof by the pin receiving portion 111 .
- the belt unit 600 rotates in the counterclockwise direction in the figures with the holding pin 606 as an axis, while the holding pin 606 itself moves downward. As a result, the state of the belt unit 600 changes to that shown in FIG. 5 .
- the belt unit 600 is pulled upward from the upper side in FIG. 5 .
- the bearing member 605 provided to the belt unit 600 is apart from the bearing fitted portion 112 of the main body housing 110 .
- the pin receiving portion 111 of the main body housing 110 does not restrain the holding pin 606 provided to the belt unit 600 from moving upward.
- the belt unit 600 is allowed to be removed from the image forming apparatus 1 .
- FIGS. 4 to 6 a procedure mounting the belt unit 600 on the image forming apparatus 1 is described with reference to FIGS. 4 to 6 .
- the image forming apparatus 1 is supposed to be as shown in FIG. 5 and to have the belt unit 600 removed in an initial state.
- a closing operation to close the movable housing 120 opened with respect to the main body housing 110 is performed.
- the belt unit 600 is inserted downward from the upper side in FIG. 5 into an opening portion formed by the main body housing 110 and the movable housing 120 .
- the holding pin 606 provided on the inner heating roller 612 side (upper side) of the belt unit 600 is inserted from upward into the pin receiving portion 111 provided to the main body housing 110 .
- the bearing member 605 bumps into the flat portion 114 of the main body housing 110 at a part of the peripheral surface of the bearing member 605 , and stops after moving to a position where another part of the peripheral surface of the bearing member 605 bumps into the regulation portion 124 of the movable housing 120 .
- the fastening members 130 which fasten the movable housing 120 to the main body housing 110 are removed from the lateral side.
- the movable housing 120 attempts to move in a direction (in the counterclockwise direction in the figures) in which the movable housing 120 is closed with respect to the main body housing 110 because the movable housing 120 is pulled toward the main body housing 110 by the unillustrated spring connected between the main body housing 110 and the movable housing 120 .
- the regulation portion 124 attached to the movable housing 120 then presses the bearing member 605 provided to the belt unit 600 toward the bearing fitted portion 112 provided to the main body housing 110 with the force received from the unillustrated spring.
- the bearing member 605 of the belt unit 600 moves while sliding on the flat portion 114 and the sloping portion 113 , which are provided to the main body housing 110 . Accordingly, the belt unit 600 on the fixing roller 611 side moves toward the main body housing 110 .
- the movable housing 120 further rotates in the counterclockwise direction in the figures. Then, instead of the regulation portion 124 , the pressing member 122 bumps into the bearing member 605 of the belt unit 600 , in accordance with the rotation of the movable housing 120 . Along with this, the bearing member 605 of the belt unit 600 rises on the sloping portion 113 while being pressed by the spring 123 and the pressing member 122 , thereby to be fitted into the bearing fitted portion 112 .
- the fixing belt 610 on a side coming into contact with the peeling pad 64 first bumps into the pressure roller 62 , and the bearing member 605 engages with the bearing fitted portion 112 of the main body housing 110 . Further, the fixing belt 610 on a side coming into contact with the fixing roller 611 bumps into the pressure roller 62 . At this time, on the inner heating roller 612 side (upper side) of the belt unit 600 , the holding pin 606 is loosely fitted into the pin receiving portion 111 provided to the main body housing 110 .
- the holding pin 606 moves upward in the state where the holding pin 606 is restrained from moving in the lateral direction thereof by the pin receiving portion 111 . That is, as a whole, the belt unit 600 rotates in the clockwise direction in the figures with the holding pin 606 as an axis, while the holding pin 606 itself moves upward.
- the outer heating roller 613 attached to the support portion 121 provided to the movable housing 120 comes into contact with the fixing belt 610 provided to the belt unit 600 .
- the movable housing 120 gets closed with respect to the main body housing 110 .
- the bearing member 605 provided to the belt unit 600 is pressed by the pressing member 122 provided to the movable housing 120 , thereby to get fitted into the bearing fitted portion 112 of the main body housing 110 .
- the first movable opening 125 provided to the movable housing 120 reaches a position at which the first movable opening 125 overlaps with the first fixed opening 115 provided to the main body housing 110 .
- the fastening members 130 which are previously removed, are prepared and inserted from the upper side so that the fastening pin 132 of each fastening member 130 penetrates the first fixed opening 115 and the first movable opening 125 .
- the movable housing 120 is fastened in a closed state with respect to the main body housing 110 .
- positioning of the belt unit 600 with respect to the pressure roller 62 provided to the main body housing 110 and positioning of the outer heating roller 613 provided to the movable housing 120 with respect to the belt unit 600 are performed by the main body housing 110 and the movable housing 120 . That is, the state of the belt unit 600 , the pressure roller 62 and the outer heating roller 613 changes to that shown in FIG. 4 , thereby to form the fixing unit 60 .
- the fixing roller 611 provided to the belt unit 600 receives force from the pressure roller 62 in a direction extending from the rotation center of the pressure roller 62 to that of the fixing roller 611 , in a state where the belt unit 600 is attached to the image forming apparatus 1 .
- the bearing member 605 provided at each of the ends in the axial direction of the fixing roller 611 is fitted into the bearing fitted portion 112 provided to the main body housing 110 .
- the bearing fitted portion 112 is formed so as to extend to a position where the bearing fitted portion 112 faces a direction in which the fixing roller 611 receives force from the pressure roller 62 . This configuration causes the force which the fixing roller 611 receives from the pressure roller 62 not to separate the bearing member 605 from the main body housing 110 .
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Abstract
Description
- This application is based on and claims priority under 35 USC §119 from Japanese Patent Application No. 2009-279502 filed Dec. 9, 2009.
- 1. Technical Field
- The present invention relates to a fixing device and an image forming apparatus that fixes an unfixed toner image on a recording medium.
- 2. Related Art
- As a fixing device used for an image forming apparatus of a copying machine or a printer, one such device having a heating member constituted by a belt member (a fixing belt) provided with tension by plural rollers is known.
- According to an aspect of the present invention, there is provided a fixing device including: a belt unit that includes a first roller member, a second roller member provided above the first roller member, a belt member rotating while being laid around the first roller member and the second roller member, and a positioning member rotatably holding the first roller member and being used for positioning of the first roller member; a pressure member that is provided below the first roller member and comes into pressure-contact with an outer peripheral surface of the belt member at a position where the pressure member faces the first roller member, thereby to form a fixing pressure portion between the pressure member and the belt member, the fixing pressure portion allowing a recording medium carrying an unfixed toner image to pass therethrough; a first housing that includes a concave portion and a sloping portion formed therein and supports the positioning member, the concave portion opening toward a lateral direction, the sloping portion sloping downward from an edge portion of a lower side of the concave portion; and a second housing that presses the positioning member so that the positioning member is fitted into the concave portion, in accordance with a closing operation to move in a direction in which the second housing is closed with respect to the first housing.
- Exemplary embodiment of the present invention will be described in detail based on the following figures, wherein:
-
FIG. 1 is a diagram showing a configuration example of an image forming apparatus to which a fixing device according to the exemplary embodiment is applied; -
FIG. 2 is a sectional configuration diagram for illustrating a configuration of the fixing unit; -
FIG. 3 is a diagram for illustrating a configuration of the belt unit in the fixing unit; -
FIG. 4 is a diagram for illustrating a state in which the belt unit is mounted and positioned on the image forming apparatus; -
FIG. 5 is a diagram for illustrating a state in which the belt unit is exposed in the image forming apparatus in order to replace the belt unit; and -
FIG. 6 is a top view ofFIG. 4 seen from a VI direction. - An exemplary embodiment of the present invention is described below in detail with reference to the accompanying drawings.
-
FIG. 1 is a diagram showing a configuration example of animage forming apparatus 1 to which a fixing device (fixing unit) 60 according to the present exemplary embodiment is applied. Theimage forming apparatus 1 shown inFIG. 1 is a so-called “tandem-type” color printer, and includes: animage forming portion 10 which forms an image on the basis of image data; amain controller 50 which controls operations of the entireimage forming apparatus 1, performs communications with a personal computer (PC) and performs image processing on image data and the like, for example; and a user interface (UI)unit 90 which accepts an input operation made by the user and displays various information for the user. - The
image forming portion 10, which is an example of a toner image forming unit, is a functional portion which forms an image through an electrophotographic system for example, and includes siximage forming units photoconductive drum 12 on which an electrostatic latent image is formed and thereafter a toner image of each color is formed; acharging device 13 which charges the surface of thephotoconductive drum 12 at a predetermined electric potential; anexposure device 14 which exposes thephotoconductive drum 12 on the basis of image data, thephotoconductive drum 12 charged by thecharging device 13; a developingdevice 15 which develops the electrostatic latent image formed on thephotoconductive drum 12 by using a toner of each color; and acleaner 16 which cleans the surface of thephotoconductive drum 12 after transfer. - The developing
devices 15 of the respective image forming units 11 are connected through toner transport paths (not shown) totoner containers - The image forming units 11 have similar configurations except toners housed in the respective developing
devices 15, and form toner images of the respective colors of cyan (C), magenta (M), high-saturation cyan (HC), high-saturation magenta (HM), yellow (Y) and black (K). Here, HC has a hue of cyan, and has a light color tone and high saturation relative to those of C. HM has a hue of magenta, and has a light color tone and high saturation relative to those of M. - The
image forming portion 10 also includes: anintermediate transfer belt 20 on which the color toner images formed on thephotoconductive drums 12 of the respective image forming units 11 are transferred; primary-transfer rollers 21 which transfer (primary-transfer) the color toner images on theintermediate transfer belt 20, the color toner images being formed by the image forming units 11; a secondary-transfer roller 22 which collectively transfers (secondary-transfers), to a sheet that is a recording medium (recording sheet), the color toner images transferred on theintermediate transfer belt 20 in a superimposing manner; and thefixing unit 60 as an example of a fixing unit (fixing device) which fixes the secondary-transferred color toner images on the sheet. - In addition, the
image forming portion 10 includes: acooling unit 80 which cools the color toner images fixed on the sheet by thefixing unit 60 so as to facilitate the fixing of the color toner images on the sheet; and acurl correcting unit 85 which corrects curl of the sheet. - Note that, in the
image forming apparatus 1 of the present exemplary embodiment, theintermediate transfer belt 20, the primary-transfer rollers 21 and the secondary-transfer roller 22 constitute a transfer unit. Further, hereinafter, a region in which the secondary-transfer roller 22 is placed to secondary-transfer the color toner images, which have been transferred on theintermediate transfer belt 20, onto the sheet will be referred to as “secondary-transfer region Tr.” - The
image forming portion 10 also includes, as a sheet transporting system: multiple (two in the present exemplary embodiment)sheet containers feed rollers sheet containers sheet container 40A; a second transport path R2 which is used for transporting a sheet fed from thesheet container 40B; a third transport path R3 which is used for transporting the sheet fed from thesheet container fixing unit 60, thecooling unit 80 and thecurl correcting unit 85; and a fifth transport path R5 which is used for transporting the sheet from thecurl correcting unit 85 toward asheet stacking unit 44 provided to an output portion of theimage forming apparatus 1. - Transport rollers or transport belts are arranged on each of the first to fifth transport paths R1 to R5 to sequentially transport sheets fed on their corresponding path.
- The
image forming portion 10 also includes, as a duplex transporting system: anintermediate sheet container 42 which once holds a sheet on a first surface of which the color toner images are fixed by thefixing unit 60; a sixth transport path R6 which is used for transporting a sheet from thecurl correcting unit 85 toward theintermediate sheet container 42; a seventh transport path R7 which is used for transporting a sheet housed in theintermediate sheet container 42 toward the third transport path R3; arouting mechanism 43 which is arranged downstream of thecurl correcting unit 85 in a sheet transport direction, and selects the route of a sheet between the fifth transport path R5 and the sixth transport path R6, the fifth transport path R5 used for transporting the sheet toward thesheet stacking unit 44, the sixth transport path R6 used for transporting the sheet toward theintermediate sheet container 42;feed rollers 45 which feed a sheet housed in theintermediate sheet container 42 and transport the sheet toward the seventh transport path R7. - Next, a basic image forming operation performed by the
image forming apparatus 1 according to the present exemplary embodiment is described. - The image forming units 11 of the
image forming portion 10 form toner images of the respective colors of C, M, HC, HM, Y and K with an electrophotographic process using the functional members described above. The color toner images formed by the respective image forming units 11 are primary-transferred on theintermediate transfer belt 20 sequentially by the primary-transfer rollers 21, so that a combined toner image in which the color toners are superimposed is formed. With the movement of the intermediate transfer belt 20 (in its arrow direction), the combined toner image on theintermediate transfer belt 20 is transported to the secondary-transfer region Tr in which the secondary-transfer roller 22 is arranged. - Meanwhile, in the sheet transporting system, the
feed rollers sheet container sheet containers UI unit 90, for example. The sheet fed by thefeed roller - In the secondary-transfer region Tr, the combined toner image held on the
intermediate transfer belt 20 is secondary-transferred on the sheet collectively with a transfer electric field formed by the secondary-transfer roller 22. - The sheet on which the combined toner image is transferred is thereafter separated from the
intermediate transfer belt 20, and transported to thefixing unit 60 along the fourth transport path R4. Thefixing unit 60 performs a fixing process on the combined toner image formed on the sheet transported thereto, and thereby fixes the toner image on the sheet. The sheet having the fixed image formed thereon is then cooled by thecooling unit 80, and its curl is corrected by thecurl correcting unit 85. The sheet having passed through thecurl correcting unit 85 is thereafter routed by therouting mechanism 43. In the case of simplex printing, the sheet is guided to the fifth transport path R5 so as to be transported toward thesheet stacking unit 44. - Note that, the toner attached to each
photoconductive drum 12 after the primary-transfer (primary-transfer residual toner) is removed by thecorresponding cleaner 16, and the toner attached to theintermediate transfer belt 20 after the secondary-transfer (secondary-transfer residual toner) is removed by abelt cleaner 26. - In the case of duplex printing, the sheet, on the first surface of which the fixed image is formed through the aforementioned process, passes through the
curl correcting unit 85 and is then guided by therouting mechanism 43 to the sixth transport path R6 so as to be transported toward theintermediate sheet container 42. Then, thefeed rollers 45 rotate in concert with the start timing of an image forming operation for a second surface performed by the image forming units 11, and the sheet is thereby fed from theintermediate sheet container 42. The sheet fed by thefeed rollers 45 is transported to the secondary-transfer region Tr along the seventh and third transport paths R7 and R3. - In the secondary-transfer region Tr, as in the case of the operation for the first surface, color toner images for the second surface which are held on the
intermediate transfer belt 20 are secondary-transferred on the sheet collectively with a transfer electric field formed by the secondary-transfer roller 22. - The sheet, both surfaces of which the toner images are formed, is subjected to the fixing process by the
fixing unit 60, cooled by thecooling unit 80, and its curl is corrected by thecurl correcting unit 85, as in the case of the operation for the first surface. The sheet having passed through thecurl correcting unit 85 is then guided by therouting mechanism 43 to the fifth transport path R5 so as to be transported toward thesheet stacking unit 44. - The image forming process of the
image forming apparatus 1 is repeatedly performed in the aforementioned manner until cycles corresponding to the number of sheets to be printed have elapsed. - Next, the
fixing unit 60 employed in theimage forming apparatus 1 according to the present exemplary embodiment is described. -
FIG. 2 is a sectional configuration diagram for illustrating a configuration of the fixingunit 60 according to the present exemplary embodiment. The fixingunit 60 is mainly formed of: a fixingbelt module 61 heating a sheet; anouter heating roller 613 as an example of an outer heating member which heats a fixingbelt 610 provided to the fixingbelt module 61, while tensioning the fixingbelt 610 from the outer side thereof; and apressure roller 62 as an example of a pressure member which is configured in such a way that thepressure roller 62 may come into contact with and separate from the fixingbelt module 61. - The fixing
belt module 61 includes: the fixingbelt 610 as an example of a belt member which moves circularly; a fixingroller 611 as an example of a first roller member which rotates while tensioning the fixingbelt 610, and heats the fixingbelt 610 from the inner side thereof at a nip portion N as an example of a fixing pressure portion that is a region where the fixingbelt module 61 and thepressure roller 62 are in pressure-contact with each other (i.e., in contact with each other while pressing each other); aninner heating roller 612 as an example of a second roller member which heats the fixingbelt 610 while tensioning the fixingbelt 610 from the inner side thereof. Additionally, the fixingbelt module 61 includes: atension roller 614 which tensions the fixingbelt 610 between the fixingroller 611 and the inner heating roller 612 (i.e., at the upstream side of the nip portion N in a belt movement direction); apeeling pad 64 as an example of a peeling member which is arranged downstream of the nip portion N in the belt movement direction and near the fixingroller 611; atension roller 615 which tensions the fixingbelt 610 between the nip portion N and the outer heating roller 613 (at the downstream side of the nip portion N in the belt movement direction); and asupport roller 616 which supports the fixingbelt 610 while receiving pressing force from theouter heating roller 613. - The fixing
belt 610 is formed of: a base layer which is made of polyimide resin; an elastic body layer which is stacked on the surface (outer peripheral surface) of the base layer and made of silicone rubber; and a release layer which covers the elastic body layer and is made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin), for example. Here, the elastic body layer is provided for improving quality of color images in particular. To be more specific, the elastic body layer is provided for the following reason. A toner image held on the sheet on which the toner image is to be fixed is formed by stacking powdery color toners. Accordingly, in order to uniformly heat the entire toner image at the nip portion N, the front surface of the fixingbelt 610 may be deformed to follow the surface irregularities of the toner image on the sheet. - The fixing
roller 611 is a cylindrical roller made of aluminum or SUS, for example. The fixingroller 611 is rotated in its arrow direction inFIG. 2 by the rotational driving force of an unillustrated driving motor, and heated to a predetermined temperature (150° C., for example) by threehalogen heaters 71, for example, as an example of a heat source placed inside the fixingroller 611. - The
inner heating roller 612 is a cylindrical roller made of aluminum or SUS, for example. Theinner heating roller 612 is heated to a predetermined temperature (190° C., for example) by fourhalogen heaters 72, for example, as an example of a heat source placed inside theinner heating roller 612. - Moreover, a spring member (not shown) is arranged at both end portions of the
inner heating roller 612. The spring member presses the fixingbelt 610 from the inner side thereof, and thereby sets the tension of theentire fixing belt 610 at, for example, 15 kgf. - The
inner heating roller 612 is further provided with a mechanism (not shown) for controlling the meandering (belt walk) of the fixingbelt 610. - The
peeling pad 64 is a block member formed of metal such as SUS or resin, for example, and having an arc-shaped cross section. Thepeeling pad 64 is fixedly arranged over the entire area of the fixingroller 611 in its axial direction at a position downstream of a region where thepressure roller 62 is to come into pressure-contact with the fixingroller 611 with the fixingbelt 610 interposed therebetween (such a region is hereinafter called a “roller nip portion N1”). Thepeeling pad 64 is arranged to uniformly press, at a predetermined load (at an average of 10 kgf, for example), thepressure roller 62 in a predetermined width region (over a nip width of 5 mm in the movement direction of the fixingbelt 610, for example) with the fixingbelt 610 interposed therebetween. Such a width region forms a “peeling pad nip portion N2” adjacent to the roller nip portion N1. - The
outer heating roller 613 has its base made of aluminum or SUS, for example, and is a cylindrical roller formed by a surface thereof being subjected to nitriding, for example. Theouter heating roller 613 is heated to a predetermined temperature (190° C., for example) by threehalogen heaters 73, for example, placed inside theouter heating roller 613. - As described above, the fixing
unit 60 of the present exemplary embodiment employs a configuration in which the fixingbelt 610 is heated by the fixingroller 611, theinner heating roller 612 and theouter heating roller 613. - Note that, in the fixing
belt module 61, the fixingbelt 610, the fixingroller 611, theinner heating roller 612, thetension roller 614, thetension roller 615, thesupport roller 616 and thepeeling pad 64 except theouter heating roller 613 configure abelt unit 600 provided to theimage forming apparatus 1 so as to be attachable and detachable. Detail of thebelt unit 600 will be described later. - The
pressure roller 62 has, as its base, a cylindrical roller made of aluminum or SUS, for example, and has an elastic layer made of silicone rubber, and a release layer made of a PFA tube which are stacked in this order from the base side. Thepressure roller 62 is arranged in such a way that it may come into contact with and separate from the fixingbelt module 61. When thepressure roller 62 is in contact with the fixingbelt module 61 while pressing the fixing belt module 61 (i.e., in pressure-contact therewith), thepressure roller 62 is rotated with the rotation of the fixingroller 611 of the fixingbelt module 61 in its arrow direction. - Next, a fixing operation performed by the fixing
unit 60 of the present exemplary embodiment is described. - In the
image forming apparatus 1, a combined toner image (unfixed toner image) is electrostatically transferred on the sheet in the secondary-transfer region Tr (seeFIG. 1 ), and the sheet is then transported toward the nip portion N (seeFIG. 2 ) of the fixingunit 60 along the fourth transport path R4 (seeFIG. 1 ). When the sheet passes through the nip portion N, the unfixed toner image on the sheet is fixed on the sheet mainly by pressure and heat acting on the roller nip portion N1. - To be more specific, in the fixing
unit 60 of the present exemplary embodiment, heat to act on the roller nip portion N1 is supplied mainly through the fixingbelt 610. The fixingbelt 610 is heated by: heat supplied by thehalogen heaters 71 placed inside of the fixingroller 611 through the fixingroller 611; heat supplied by thehalogen heaters 72 placed inside of theinner heating roller 612 through theinner heating roller 612; and heat supplied by thehalogen heaters 73 placed inside of theouter heating roller 613 through theouter heating roller 613. This configuration allows thermal energy to be supplied not only through the fixingroller 611 but also through theinner heating roller 612 and theouter heating roller 613. Accordingly, a sufficient amount of heat supply is secured in the roller nip portion N1 even at a high process speed. - In the fixing
unit 60 of the present exemplary embodiment, the fixingbelt 610 serving as a direct fixing member may have a configuration with extremely low heat capacity. In addition, the fixingbelt 610 is configured to be in contact with each of the fixingroller 611, theinner heating roller 612, and theouter heating roller 613, which are heat supplying members, in a large wrap area (wrap angle). This configuration allows a sufficient amount of heat to be supplied through the fixingroller 611, theinner heating roller 612, and theouter heating roller 613 in a short period in which the fixingbelt 610 makes one rotation, and thereby allows the fixingbelt 610 to come back to a required fixing temperature within a short time period. Hence, the predetermined fixing temperature is maintained in the roller nip portion N1. - As a consequence, with the fixing
unit 60 of the present exemplary embodiment, a fixing temperature is maintained within a certain range even when sheets are continuously fed at a high speed. Moreover, a phenomenon in which the fixing temperature drops at the start of high-speed fixing operation (so-called a “temperature droop phenomenon”) is suppressed. These effects of the maintenance of the fixing temperature and the suppression of the temperature droop phenomenon also hold for the fixing operation especially on heavy paper or the like having high heat capacity. Further, even if the fixing temperature needs to be changed (including both increase and decrease of the fixing temperature) halfway through a printing operation in accordance with types of sheets, such a temperature change is easily performed by adjusting the outputs of thehalogen heaters 71 to 73 owing to the low heat capacity of the fixingbelt 610. - Further, in the fixing
unit 60 of the present exemplary embodiment, the fixingroller 611 is a hard roller made of aluminum, SUS, or the like, while thepressure roller 62 is a soft roller made by covering the elastic layer. Accordingly, in the roller nip portion N1, a nip region having a certain width in the movement direction of the fixingbelt 610 is formed by thepressure roller 62 being bent at its surface with the fixingroller 611 being hardly bent. As described above, in the roller nip portion N1, the fixingroller 611 around which the fixingbelt 610 is wound is hardly deformed. This allows the fixingbelt 610 to pass through the roller nip portion N1 while fluctuation of moving speed of the fixingbelt 610 is suppressed, and thereby restrains wrinkles and deformation from occurring in the fixingbelt 610 at the roller nip portion N1. As a result, fixed images with good quality are stably provided. - After passing through the roller nip portion N1, the sheet is subsequently transported to the peeling pad nip portion N2. At the peeling pad nip portion N2, the
pressure roller 62 presses thepeeling pad 64, and thereby comes into pressure-contact with the fixingbelt 610. Such a configuration causes the peeling pad nip portion N2 to have curving upward with the curvature of thepressure roller 62, while the roller nip portion N1 has a shape curving downward with the curvature of the fixingroller 611. - Due to the above configuration, the sheet, which has been heated and pressurized with the curvature of the fixing
roller 611 in the roller nip portion N1, is caused to change its movement direction in the peeling pad nip portion N2 along the curvature of thepressure roller 62, which is opposite to the current direction. In this event, an extremely little slippage occurs between the toner image on the sheet and the surface of the fixingbelt 610. This weakens the adhesion force between the toner image and the fixingbelt 610, and thereby makes the sheet likely to be peeled from the fixingbelt 610. In this way, the peeling pad nip portion N2 may be regarded as a region where a preparation step is carried out for ensuring reliable peeling in a final peeling step. - Since the fixing
belt 610 is transported so as to be wound around thepeeling pad 64 at the exit of the peeling pad nip portion N2, the transport direction of the fixingbelt 610 is changed there. In other words, since the fixingbelt 610 moves along the outer side surface of thepeeling pad 64, the fixingbelt 610 is bent to a large extent at the exit of the peeling pad nip portion N2. For this reason, the sheet, whose adhesion force to the fixingbelt 610 has been weakened in advance in the peeling pad nip portion N2, is peeled from the fixingbelt 610 by the stiffness of the sheet itself. - The sheet having been peeled from the fixing
belt 610 is then moved in a direction guided by a peelingguide plate 69 which is arranged downstream of the peeling pad nip portion N2. The sheet having been guided by the peelingguide plate 69 is thereafter transported toward the coolingunit 80 by asheet exit guide 78 and asheet exit belt 79. The fixing process in the fixingunit 60 is completed with the above-described operation. -
FIG. 3 is a diagram for illustrating a configuration of thebelt unit 600 in the fixingunit 60. Note thatFIG. 3 shows a side elevational view of thebelt unit 600 seen from the front side thereof inFIG. 1 . - The
belt unit 600 includes: asupport housing 601 which is formed of metal, such as SUS, rotatably supports roller members, such as the fixingroller 611, thetension roller 614, thetension roller 615 and thesupport roller 616, and supports members, such as thepeeling pad 64, in a fixed state; and aroller support member 602 which is formed of metal, such as SUS, rotatably supports theinner heating roller 612. Here, theroller support member 602 is supported by aslide support member 603 arranged between thesupport housing 601 and theroller support member 602 so as to slide (move in parallel) in the direction of arotation axis 612 a of theinner heating roller 612. Additionally, theroller support member 602 supports therotation axis 612 a of theinner heating roller 612 by using aroller support portion 602 a. This configuration allows theinner heating roller 612 to rotate through a bearing (not shown) arranged between theinner heating roller 612 and therotation axis 612 a supported by theroller support portion 602 a. - Here, the
roller support portion 602 a supporting therotation axis 612 a of theinner heating roller 612 is provided with alow friction portion 602 b made of a low friction member such as PFA, for example, which lowers sliding resistance between therotation axis 612 a and theroller support portion 602 a. - In addition, the
support housing 601 includes aroller biasing member 604 attached thereto. Theroller biasing member 604 biases theroller support member 602 toward therotation axis 612 a of theinner heating roller 612. Theroller biasing member 604 applies force toward an outer side (upward inFIG. 3 ) to theinner heating roller 612 with theroller support member 602 interposed therebetween, and thereby sets predetermined tension to the fixingbelt 610 which tensions theinner heating roller 612. - Further, a
rotation axis 611 a of the fixingroller 611 is arranged in such a way that therotation axis 611 a penetrates a bore provided to thesupport housing 601 to project into the front side of thesupport housing 601 inFIG. 3 . Additionally, an unillustrated bearing is provided at a position where the bore is formed. Thesupport housing 601 rotatably supports therotation axis 611 a of the fixingroller 611. - A bearing
member 605 which is rotatable with respect to therotation axis 611 a is mounted on a portion of therotation axis 611 a of the fixingroller 611, the portion being arranged so as to project toward the outer side from thesupport housing 601. The bearingmember 605 as an example of a positioning member is used for an operation to attach or detach thebelt unit 600 and positioning of thebelt unit 600 with respect to theimage forming apparatus 1. - Furthermore, a holding
pin 606 which projects toward the front side inFIG. 3 is attached to thesupport housing 601 on theinner heating roller 612 side thereof. The holdingpin 606 as an example of a second positioning member is used for an operation to attach or detach thebelt unit 600 and positioning of thebelt unit 600 with respect to theimage forming apparatus 1, as well as the bearingmember 605 mentioned above. - Note that the
support housing 601 and theroller support member 602 are provided to the fixingroller 611 and the like on each of the front and rear sides inFIG. 3 . Theslide support member 603, theroller biasing member 604, the bearingmember 605 and the holdingpin 606 are also provided on each of the front and rear sides inFIG. 3 , respectively. - Additionally, a gear (not shown) for receiving driving force from the driving motor (not shown) provided on the main body of the
image forming apparatus 1 is attached to therotation axis 611 a of the fixingroller 611 projecting toward the rear side inFIG. 3 . - Next, a mounting structure of the
belt unit 600 on theimage forming apparatus 1 is described. -
FIG. 4 is a diagram for illustrating a state in which thebelt unit 600 is mounted and positioned on theimage forming apparatus 1. -
FIG. 5 is a diagram for illustrating a state in which thebelt unit 600 is exposed in theimage forming apparatus 1 in order to replace the belt unit. - Further,
FIG. 6 is a top view ofFIG. 4 seen form a VI direction. - The
image forming apparatus 1 of the present exemplary embodiment includes: amain body housing 110 which is mounted on theimage forming apparatus 1 in a fixed state, and rotatably supports thepressure roller 62 constituting the fixingunit 60; amovable housing 120 which is attached to themain body housing 110 so as to be openable and closeable. Here, themain body housing 110 as an example of a first housing and themovable housing 120 as an example of a second housing are rotatably connected with each other by anaxis 100 provided below. Additionally, themain body housing 110 and themovable housing 120 are connected with each other by an unillustrated spring above theaxis 100. This unillustrated spring restrains themovable housing 120 from rotating in the clockwise direction inFIG. 4 around theaxis 100 with respect to themain body housing 110. Rotation of themovable housing 120 in the clockwise direction inFIG. 4 around theaxis 100 with respect to themain body housing 110 exposes thebelt unit 600 to the outside. Meanwhile, rotation of themovable housing 120 in the counterclockwise direction inFIG. 4 around theaxis 100 with respect to themain body housing 110 covers thebelt unit 600 from the outside. - The
main body housing 110 is formed of two side plates connected with a member extending from the front side to the rear side inFIG. 4 . Here, the two side plates are obtained by performing a mechanical process on a metal plate, for example, and are respectively provided on the front side and the rear side of a mounting portion of thebelt unit 600. - The
main body housing 110 is provided with apin receiving portion 111 which opens upward and is used for inserting the holdingpin 606 attached to thesupport housing 601 of thebelt unit 600. Thepin receiving portion 111 as an example of a receiving portion is formed in such a way that thepin receiving portion 111 has a slightly larger diameter than that of the holdingpin 606 in an upper region which is an entrance/exit of the holdingpin 606, and has a larger diameter in a lower region than in the upper region. - Additionally, the
main body housing 110 is provided with a bearing fittedportion 112 which opens toward a lateral side facing themovable housing 120, and into which the bearingmember 605 of thebelt unit 600 is fitted. The bearing fittedportion 112 as an example of a concave portion has a semicircular opening shape along the bearingmember 605. The bearing fittedportion 112 is provided with, at the lower end portion thereof: a slopingportion 113 formed in such a way that an edge thereof is lowered with a slope toward themovable housing 120; and aflat portion 114 which is connected to the slopingportion 113 and has a flat edge. - Further, the
main body housing 110 includes: a firstfixed opening 115 provided at the upside thereof in the up-and-down direction; and a secondfixed opening 116 provided at a position that is horizontal with theaxis 100 on a distal side seen from thepressure roller 62 with respect to a position where theaxis 100 is formed. - On the other hand, the
movable housing 120 is formed of a material obtained by resin molding or the like, for example, and has an L-shaped cross section. - The
movable housing 120 is provided with asupport portion 121 which rotatably supports theouter heating roller 613 constituting the fixingunit 60. This configuration allows theouter heating roller 613 to rotate around theaxis 100 in accordance with themovable housing 120. - Additionally, the
movable housing 120 includes apressing member 122 attached thereto. As shown inFIG. 4 , the pressingmember 122 presses the bearingmember 605 against an edge of theinner heating roller 612 by pressing the bearingmember 605 fitted into the bearing fittedportion 112 of themain body housing 110 toward themain body housing 110 from a lateral side of the bearingmember 605, when themovable housing 120 is closed with respect to themain body housing 110 in a state where thebelt unit 600 is arranged. The pressingmember 122 as an example of a second pressing member is attached to themovable housing 120 through aspring 123 as an example of an elastic member, so as to be capable of advancing and retracting with respect to themovable housing 120. - Further, the
movable housing 120 includes aregulation portion 124 formed therein. As shown inFIG. 5 , theregulation portion 124 regulates further movement of the bearingmember 605 by coming into contact with the bearingmember 605, when themovable housing 120 is opened with respect to themain body housing 110 in the state where thebelt unit 600 is arranged, and the bearingmember 605 is removed from the bearing fittedportion 112 provided to themain body housing 110. Theregulation portion 124 has a structure in which two flat surfaces are connected with each other by one sloping surface. The height of a flat surface at a portion of theregulation portion 124 adjacent to thepressing member 122 is the same as that of a surface of thepressing member 122. Moreover, theregulation portion 124 functions as a first pressing member which presses the bearingmember 605 toward the bearing fittedportion 112, as will be described later. - Furthermore, the
movable housing 120 includes: a firstmovable opening 125 provided on an upper edge thereof; and a secondmovable opening 126 provided on a lower edge thereof. - In the present exemplary embodiment, the first fixed
opening 115 provided to themain body housing 110 and the firstmovable opening 125 provided to themovable housing 120 overlap each other when themovable housing 120 is closed with respect to themain body housing 110, as shown inFIG. 4 . - On the other hand, in the present exemplary embodiment, the second
fixed opening 116 provided to themain body housing 110 and the secondmovable opening 126 provided to themovable housing 120 overlap each other when themovable housing 120 is opened with respect to themain body housing 110, as shown inFIG. 5 . - The
image forming apparatus 1 further includesfastening members 130. Thefastening members 130 fasten themovable housing 120 to themain body housing 110 by penetrating the first fixedopening 115 and the firstmovable opening 125, which are overlapped each other, when themovable housing 120 is closed with respect to themain body housing 110, as shown inFIGS. 4 and 6 , for example. Additionally, thefastening members 130 fasten themovable housing 120 to themain body housing 110 by penetrating the secondfixed opening 116 and the secondmovable opening 126, which are overlapped each other, when themovable housing 120 is opened with respect to themain body housing 110, as shown inFIG. 5 , for example. Each of thefastening members 130 includes: agrip portion 131 for a user to hold by hand; and afastening pin 132 which is attached to thegrip portion 131 and is capable of being inserted into each of the aforementioned openings. - <Explanation of Procedure Removing Belt Unit from Image Forming Apparatus>
- Next, a procedure removing the
belt unit 600 from theimage forming apparatus 1 is described with reference toFIGS. 4 to 6 . Here, theimage forming apparatus 1 is supposed to be as shown inFIG. 4 in an initial state. When thebelt unit 600 gets removed from theimage forming apparatus 1, an opening operation to open themovable housing 120 closed with respect to themain body housing 110 is performed. - First, the
fastening members 130 which fasten themovable housing 120 to themain body housing 110 are removed from above. This causes themovable housing 120 to be rotatable around theaxis 100 with respect to themain body housing 110. However, removal of thefastening members 130 does not release themovable housing 120 with respect to themain body housing 110 because themovable housing 120 is pulled toward themain body housing 110 by the unillustrated spring connected between themain body housing 110 and themovable housing 120. - Next, when force in the clockwise direction in the figures around the
axis 100 is applied to themovable housing 120 through the firstmovable opening 125, for example, themovable housing 120 starts rotating in the clockwise direction in the figures while resisting the pulling force of the unillustrated spring. - Along with rotation of the
movable housing 120 in the clockwise direction in the figures, the pressingmember 122 provided to themovable housing 120 moves in a direction apart from the bearingmember 605 provided to thebelt unit 600 held in themain body housing 110. Additionally, theouter heating roller 613 attached to thesupport portion 121 provided to themovable housing 120 also separates from the fixingbelt 610 provided to thebelt unit 600. As a consequence, in thebelt unit 600, the bearingmember 605 is pressed on an upper edge of the bearing fittedportion 112 by thepressure roller 62, while the holdingpin 606 is held on themain body housing 110 side in a state where the holdingpin 606 is loosely fitted into thepin receiving portion 111. - After that, when the
movable housing 120 is further rotated in the clockwise direction in the figures with respect to themain body housing 110, the secondmovable opening 126 provided to themovable housing 120 reaches a position at which the secondmovable opening 126 overlaps with the secondfixed opening 116 provided to themain body housing 110. In this state, thefastening members 130, which are previously removed, are prepared and inserted from a lateral side so that thefastening pin 132 of eachfastening member 130 penetrates the secondfixed opening 116 and the secondmovable opening 126. Thereby, themovable housing 120 is fastened in an opened state with respect to themain body housing 110 while resisting the pulling force of the unillustrated spring. That is, the state of themain body housing 110 and themovable housing 120 changes to that shown inFIG. 5 . Additionally, thebelt unit 600 is exposed between themain body housing 110 and themovable housing 120 in accordance with this change. - Next, when force toward the
movable housing 120 is applied to the fixingroller 611 side (lower side) of thebelt unit 600, the bearingmember 605 provided to thebelt unit 600 starts moving toward a side (right side inFIG. 5 ) being apart from the bearing fittedportion 112 of themain body housing 110. In this event, after being separated from the bearing fittedportion 112, the bearingmember 605 slides down along the slopingportion 113 of themain body housing 110 due to the gravity applied to thebelt unit 600. The bearingmember 605 having slid down along the slopingportion 113 then bumps into theflat portion 114 of themain body housing 110 at a part of the peripheral surface of the bearingmember 605, and stops by another part of the peripheral surface thereof bumping into theregulation portion 124 of themovable housing 120. At this time, on theinner heating roller 612 side (upper side) of thebelt unit 600, the holdingpin 606 is loosely fitted into thepin receiving portion 111 provided to themain body housing 110. Accordingly, in accordance with the aforementioned slide down of the bearingmember 605 along the slopingportion 113, the holdingpin 606 moves downward in a state where the holdingpin 606 is restrained from moving in the lateral direction thereof by thepin receiving portion 111. That is, as a whole, thebelt unit 600 rotates in the counterclockwise direction in the figures with the holdingpin 606 as an axis, while the holdingpin 606 itself moves downward. As a result, the state of thebelt unit 600 changes to that shown inFIG. 5 . - In this state, the
belt unit 600 is pulled upward from the upper side inFIG. 5 . At this time, the bearingmember 605 provided to thebelt unit 600 is apart from the bearing fittedportion 112 of themain body housing 110. Additionally, thepin receiving portion 111 of themain body housing 110 does not restrain the holdingpin 606 provided to thebelt unit 600 from moving upward. Thus, thebelt unit 600 is allowed to be removed from theimage forming apparatus 1. - Next, a procedure mounting the
belt unit 600 on theimage forming apparatus 1 is described with reference toFIGS. 4 to 6 . Here, theimage forming apparatus 1 is supposed to be as shown inFIG. 5 and to have thebelt unit 600 removed in an initial state. When thebelt unit 600 gets mounted on theimage forming apparatus 1, a closing operation to close themovable housing 120 opened with respect to themain body housing 110 is performed. - First, the
belt unit 600 is inserted downward from the upper side inFIG. 5 into an opening portion formed by themain body housing 110 and themovable housing 120. In this event, the holdingpin 606 provided on theinner heating roller 612 side (upper side) of thebelt unit 600 is inserted from upward into thepin receiving portion 111 provided to themain body housing 110. Meanwhile, on the fixingroller 611 side (lower side) of thebelt unit 600, the bearingmember 605 bumps into theflat portion 114 of themain body housing 110 at a part of the peripheral surface of the bearingmember 605, and stops after moving to a position where another part of the peripheral surface of the bearingmember 605 bumps into theregulation portion 124 of themovable housing 120. - Next, the
fastening members 130 which fasten themovable housing 120 to themain body housing 110 are removed from the lateral side. This causes themovable housing 120 to be rotatable around theaxis 100 with respect to themain body housing 110. Here, themovable housing 120 attempts to move in a direction (in the counterclockwise direction in the figures) in which themovable housing 120 is closed with respect to themain body housing 110 because themovable housing 120 is pulled toward themain body housing 110 by the unillustrated spring connected between themain body housing 110 and themovable housing 120. - The
regulation portion 124 attached to themovable housing 120 then presses the bearingmember 605 provided to thebelt unit 600 toward the bearing fittedportion 112 provided to themain body housing 110 with the force received from the unillustrated spring. Along with this, the bearingmember 605 of thebelt unit 600 moves while sliding on theflat portion 114 and the slopingportion 113, which are provided to themain body housing 110. Accordingly, thebelt unit 600 on the fixingroller 611 side moves toward themain body housing 110. - Thereafter, when force in the counterclockwise direction in the figures around the
axis 100 is applied to themovable housing 120, themovable housing 120 further rotates in the counterclockwise direction in the figures. Then, instead of theregulation portion 124, the pressingmember 122 bumps into the bearingmember 605 of thebelt unit 600, in accordance with the rotation of themovable housing 120. Along with this, the bearingmember 605 of thebelt unit 600 rises on the slopingportion 113 while being pressed by thespring 123 and thepressing member 122, thereby to be fitted into the bearing fittedportion 112. - In this event, in the
belt unit 600, the fixingbelt 610 on a side coming into contact with thepeeling pad 64 first bumps into thepressure roller 62, and the bearingmember 605 engages with the bearing fittedportion 112 of themain body housing 110. Further, the fixingbelt 610 on a side coming into contact with the fixingroller 611 bumps into thepressure roller 62. At this time, on theinner heating roller 612 side (upper side) of thebelt unit 600, the holdingpin 606 is loosely fitted into thepin receiving portion 111 provided to themain body housing 110. Accordingly, in accordance with the aforementioned slide up of the bearingmember 605 along the slopingportion 113, the holdingpin 606 moves upward in the state where the holdingpin 606 is restrained from moving in the lateral direction thereof by thepin receiving portion 111. That is, as a whole, thebelt unit 600 rotates in the clockwise direction in the figures with the holdingpin 606 as an axis, while the holdingpin 606 itself moves upward. - Additionally, along with rotation of the
movable housing 120 in the counterclockwise direction in the figures, theouter heating roller 613 attached to thesupport portion 121 provided to themovable housing 120 comes into contact with the fixingbelt 610 provided to thebelt unit 600. - After that, when the
movable housing 120 is further rotated in the counterclockwise direction in the figures, themovable housing 120 gets closed with respect to themain body housing 110. At this time, the bearingmember 605 provided to thebelt unit 600 is pressed by the pressingmember 122 provided to themovable housing 120, thereby to get fitted into the bearing fittedportion 112 of themain body housing 110. Additionally, when themovable housing 120 is closed with respect to themain body housing 110, the firstmovable opening 125 provided to themovable housing 120 reaches a position at which the firstmovable opening 125 overlaps with the first fixedopening 115 provided to themain body housing 110. In this state, thefastening members 130, which are previously removed, are prepared and inserted from the upper side so that thefastening pin 132 of eachfastening member 130 penetrates the first fixedopening 115 and the firstmovable opening 125. Thereby, themovable housing 120 is fastened in a closed state with respect to themain body housing 110. Moreover, along with this, positioning of thebelt unit 600 with respect to thepressure roller 62 provided to themain body housing 110 and positioning of theouter heating roller 613 provided to themovable housing 120 with respect to thebelt unit 600 are performed by themain body housing 110 and themovable housing 120. That is, the state of thebelt unit 600, thepressure roller 62 and theouter heating roller 613 changes to that shown inFIG. 4 , thereby to form the fixingunit 60. - Here, as shown in
FIG. 4 , the fixingroller 611 provided to thebelt unit 600 receives force from thepressure roller 62 in a direction extending from the rotation center of thepressure roller 62 to that of the fixingroller 611, in a state where thebelt unit 600 is attached to theimage forming apparatus 1. The bearingmember 605 provided at each of the ends in the axial direction of the fixingroller 611 is fitted into the bearing fittedportion 112 provided to themain body housing 110. The bearing fittedportion 112 is formed so as to extend to a position where the bearing fittedportion 112 faces a direction in which the fixingroller 611 receives force from thepressure roller 62. This configuration causes the force which the fixingroller 611 receives from thepressure roller 62 not to separate the bearingmember 605 from themain body housing 110. - The foregoing description of the exemplary embodiment of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The exemplary embodiment was chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
Claims (11)
Applications Claiming Priority (2)
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JP2009-279502 | 2009-12-09 | ||
JP2009279502A JP5531592B2 (en) | 2009-12-09 | 2009-12-09 | Fixing apparatus and image forming apparatus |
Publications (2)
Publication Number | Publication Date |
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US20110135341A1 true US20110135341A1 (en) | 2011-06-09 |
US8165500B2 US8165500B2 (en) | 2012-04-24 |
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Application Number | Title | Priority Date | Filing Date |
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US12/840,711 Expired - Fee Related US8165500B2 (en) | 2009-12-09 | 2010-07-21 | Fixing device and image forming apparatus |
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US (1) | US8165500B2 (en) |
JP (1) | JP5531592B2 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20120189969A1 (en) * | 2011-01-20 | 2012-07-26 | Xerox Corporation | Apparatus, systems, and methods for belt-roll fuser latching |
US20120251157A1 (en) * | 2011-03-30 | 2012-10-04 | Kyocera Mita Corporation | Image forming apparatus for performing fixing processing by induction heating system |
US8818253B2 (en) * | 2012-03-26 | 2014-08-26 | Fuji Xerox Co., Ltd. | Fixing device and image forming apparatus |
US9213282B2 (en) * | 2012-09-04 | 2015-12-15 | Fuji Xerox Co., Ltd. | Fixing device and image forming apparatus |
US9581946B2 (en) * | 2015-01-05 | 2017-02-28 | Konica Minolta, Inc. | Fixing device having heating section support with hole for releasing heat |
CN113655696A (en) * | 2020-05-12 | 2021-11-16 | 佳能株式会社 | Image heating apparatus and image forming apparatus |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
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JP5958007B2 (en) * | 2012-03-26 | 2016-07-27 | 富士ゼロックス株式会社 | Fixing device, image forming apparatus |
JP7271201B2 (en) * | 2019-01-22 | 2023-05-11 | キヤノン株式会社 | image forming device |
JP7314329B1 (en) | 2022-01-12 | 2023-07-25 | キヤノン株式会社 | Fixing device |
JP7408187B1 (en) | 2023-03-03 | 2024-01-05 | 有限会社 田中製作所 | Cardboard drilling jig and drilling method |
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US7454157B2 (en) * | 2005-09-15 | 2008-11-18 | Ricoh Company, Ltd. | Image forming device and unit position adjustment method |
US8023861B2 (en) * | 2007-12-11 | 2011-09-20 | Ricoh Company, Ltd. | Fixing device and image-forming apparatus comprising the same |
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JP4748885B2 (en) | 2001-06-21 | 2011-08-17 | 株式会社リコー | Belt fixing device and image forming apparatus |
JP5344531B2 (en) * | 2008-04-08 | 2013-11-20 | キヤノン株式会社 | Image forming apparatus having fixing unit attaching / detaching mechanism |
JP5407172B2 (en) * | 2008-05-01 | 2014-02-05 | 株式会社リコー | Fixing apparatus and image forming apparatus |
-
2009
- 2009-12-09 JP JP2009279502A patent/JP5531592B2/en not_active Expired - Fee Related
-
2010
- 2010-07-21 US US12/840,711 patent/US8165500B2/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US7454157B2 (en) * | 2005-09-15 | 2008-11-18 | Ricoh Company, Ltd. | Image forming device and unit position adjustment method |
US8023861B2 (en) * | 2007-12-11 | 2011-09-20 | Ricoh Company, Ltd. | Fixing device and image-forming apparatus comprising the same |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20120189969A1 (en) * | 2011-01-20 | 2012-07-26 | Xerox Corporation | Apparatus, systems, and methods for belt-roll fuser latching |
US8655249B2 (en) * | 2011-01-20 | 2014-02-18 | Xerox Corporation | Apparatus, systems, and methods for belt-roll fuser latching |
US20120251157A1 (en) * | 2011-03-30 | 2012-10-04 | Kyocera Mita Corporation | Image forming apparatus for performing fixing processing by induction heating system |
US8750756B2 (en) * | 2011-03-30 | 2014-06-10 | Kyocera Mita Corporation | Image forming apparatus for performing fixing processing by induction heating system |
US8818253B2 (en) * | 2012-03-26 | 2014-08-26 | Fuji Xerox Co., Ltd. | Fixing device and image forming apparatus |
US9213282B2 (en) * | 2012-09-04 | 2015-12-15 | Fuji Xerox Co., Ltd. | Fixing device and image forming apparatus |
US9581946B2 (en) * | 2015-01-05 | 2017-02-28 | Konica Minolta, Inc. | Fixing device having heating section support with hole for releasing heat |
CN113655696A (en) * | 2020-05-12 | 2021-11-16 | 佳能株式会社 | Image heating apparatus and image forming apparatus |
US11567436B2 (en) | 2020-05-12 | 2023-01-31 | Canon Kabushiki Kaisha | Image heating apparatus and image forming apparatus |
Also Published As
Publication number | Publication date |
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JP5531592B2 (en) | 2014-06-25 |
JP2011123181A (en) | 2011-06-23 |
US8165500B2 (en) | 2012-04-24 |
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